W3 Schools is one I've used and sometimes still reference. If you're looking for PHP specific things, PHP.net is a good reference but it's not a tutorial site. It's mainly a list of functions and what they do with examples.
If you are new to web development, you really have to get your HTML and CSS skills up to speed before you consider client and server side scripting which gives your site the dynamic features. Fortunately, HTML and CSS is very easy to pick up and learn.
From there, move on to the server scripting language of your choice. PHP is a natural choice for many..its open source, lots of online examples, help, etc.., but you can go with ASP.NET, JSP, etc.. You will also need to learn some SQL if you want to store data to really have a data driven site.